Veteran birder and author Scott Weidensaul calls it "one of the most enigmatic birds in North America." It's the diminutive northern saw-whet owl, Aegolius acadicus, the smallest owl in eastern North America.

Odds are you've never seen one in the Roanoke area nor heard their odd beeping, tooting call. But that doesn't mean they're not here, at least right now.

Each year beginning around Halloween, banders are up until the wee hours, trapping the migrating owls in mist nets as they head south from their breeding territories in coniferous forests of Alaska and Canada.

There's a small disjunct breeding population as far south as the mountains of North Carolina, but breeding saw-whets are not common south of Canada in the east.

Several banders have monitored saw-whet movement through Virginia for years, including professor Gene Sattler of Liberty University and retired professor Claire Mellinger of Eastern Mennonite University in Harrisonburg.

Banding can provide clues about migration routes and migration habitat, data that are important for helping to conserve the tiny nocturnal raptor.

The information suggests that the birds are possibly more numerous in Virginia than previously suspected.

"This year is apparently going to be a big year," said Mellinger. "Last year was a low year, but it appears they're somewhat cyclic."

He estimates there's a week or more of migration remaining.

A possible reason for larger numbers this fall is the coincidence of a population spike in small rodents in Ontario this spring, followed by a bad seed crop this summer. Large numbers of voles and mice led to a high survival rate for saw-whet fledglings, which then dispersed more widely than usual when prey numbers collapsed due to the small seed crop.

Mellinger has erected mist nets on a low ridge in western Rockingham County since 2001. Following banding protocol, he uses an audio lure with the saw-whet breeding call to attract birds to the net. He says it's likely there are a few saw-whets wintering in our area each year, unknown to most western Virginia birders because of the owls' secretive behavior and their tendency to remain silent outside of breeding season.

"Their little 'beep-beep-beep' call is easy to identify," Mellinger said. "But in the winter, they use their 'cat call' or other little sounds that most birders here are not that familiar with. The average birder doesn't go out at night anyway, and then the birds might not be making any noise."

A small numbers of breeding saw-whets have been found in Virginia, including three or four "probables" south of Shenandoah National Park and possibly a few individuals in Montgomery County, according to Mellinger. On Nov. 12, Blacksburg birder Matt Hafner had at least one bird respond to an audio lure.

For the latest on saw-whet migration, check out projectowlnet.org.

Two new Harveys Knob records

Hawk-watcher Bill James says 2007 is a record season for fall migrating raptors counted at Harveys Knob on the Blue Ridge Parkway.

On Nov. 17, counters at the Knob surpassed the previous record of 11,893 birds, set in 1996.

Another milestone occurred Monday when Blacksburg birder Matt Hafner saw and photographed a Townsend's solitaire at Harveys Knob.

According to Harveys Knob regular Mike Purdy, this is the first record of this mockingbird-like species in Virginia. Check out the photo at billhubick.com/others/matt_hafner.html

Other birders have converged on the site to notch a lifer for themselves, but as of Tuesday morning nobody had found the bird again.